Modern digital telecommunication systems are operating at ever-increasing data rates to accommodate society's growing demands for information exchange. However, increasing data rates, while at the same time accommodating the fixed bandwidths allocated by the Federal Communications Commission (FCC), requires increasingly sophisticated signal processing techniques. Since low cost, small size and low power consumption are portent in the hardware implementations of such communication systems, custom integrated circuit solutions are important to achieving these goals.
Next generation digital television systems, such as high-definition television (HDTV) rely on telecommunication transceivers to deliver data at rates in excess of 30 megabits per second (30 Mb/s). The ATSC A/53 Digital Television Standard, was developed by the “Digital HDTV Alliance” of U.S. television vendors, and has been accepted as the standard for terrestrial transmission of HDTV signals in the United States. The ATSC A/53 standard is based on an 8-level vestigial sideband (8-VSB) modulation format with a nominal payload data rate of 19.4 Mbps in a 6 Mhz channel.
Existing digital television (DTV) receivers rely on an equalization structure that applies a feedforward equalizer (FFE) followed by a decision feedback equalizer (DFE), each of which is updated by a decision-based tap-updating algorithm such as the least means squares (LMS) algorithm. Those receivers, due in part to the requirements of the ATSC standard, are designed to work in relatively benign Ricean channels. The receivers are typically not capable of properly functioning under severe Ricean and/or Rayleigh channel conditions. In addition, the ATSC standard does not provide sufficient redundancy in the transmitted signal to facilitate receivers in properly processing the received signal, thereby compounding the problem.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with the present invention as set forth in the remainder of the present application with reference to the drawings.